Waterproof material and process and apparatus for preparing the aggregate contained therein



E. H. CANON 'ET AL WATERPROOF MATERIAL AND PROCESS AND APPARATUS FOR PREPARING THE AGGREGATE CONTAINED THEREIN Filed Oct. 7, 1931 :1 III/1111111 1 Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE Edward H. Canon and Benjamin 6. Canon,

MeKeesport, Pa.

Application October 3,, 1931, Serial No. 567,410 14 Claims. (Cl. 91-70) This invention relates broadly to the production of waterproof material, such as plaster and paint, and specifically to the production of an improved aggregate for such material and an improved method and apparatus for commercially preparing the aggregate.

An object of the invention is to produce an improved method of treating the aggregate for waterproof material, which insures the production of uniform aggregate having improved physical characteristics and which therefore results in the production of improved waterproof material such as plaster and paint.

A further object is to produce an improved apparatus for treating aggregate in its preparation for use in waterproof material.

A further object is to produce an improved aggregate for waterproof material, such as paint or plaster.

Waterproofmaterlal such as plaster and paint consists essentially of what-may be termed a coarser aggregate and a binding agent. The socalled coarser aggregate forms the vital part and the greater proportion of the waterproof mate rial. consequently in order to produce effective material having the necessary physical characteristics it is essential-to pay particular attention to the material employed as the coarser aggregate. This aggregate should possess three physical characteristics; it should be of such character as to be readily bonded by the binding material, and it should be strong and durable. That is to say, each particle of aggregate should be a rough edged particle'and of irregular shape as distinguished, for example, from the round.

particles or substantially smooth particles which constitute the major portion or ordinary sand. Each particle should also be strong and tough, and should be capable of resisting change under 40 all conditions to which it may be subjected. In

addition to these physical characteristics, the aggregate should be uniformly distributed throughout the mass of waterproof material and in such a way as to minimize, to the greatest possible degree, the size of the voids or interstices between the particles of aggregate in the waterproof material. In order to accomplish this it is necessary to so form the aggregate that it is not only made up of particles of different size,

but also includes a more or less definite percentage of diiferent sized particles.

It is apparent that an assembly of particles of the same or approximately the same size will produce a mass having interstices or voids between the particles of substantially the same size and that the voids will be more or less uniform throughout the entire mass. In order to reduce the size of the voids within the mass it is necessary to include smaller particles which will fill or partially fill the voids between the larger par- 5 ticles. It will, of course, be apparent that the voids will be most effectively filled if various sizes of particles are employed and if the mass is made up of the proper proportions of the various sized particles. it

In the production of Waterproof material, such as here contemplated, it is essential to provide a strong bond between the binding agent and each of the particles and also between the individual particles. For this reason it is, as heretofore Mi stated, desirable to employ aggregate made up of irregular shaped particles and, as will be apparent, it is also desirable to include different sizes of these particles so that the different particles of aggregate not only cooperate to reduce the m amount of free binding agent employed, but also intermesh or, interknit with each other to produce a more or less mechanically bonded mass, wherein the different particles of the mass are permanently and rigidly held within the mass by the adherent characteristic of the binding agent.

In our reference to free binding agent we mean to say that the intent is to provide as thin a film of binding agent between adjacent particles of aggregate as is possible, so as to reduce the amount-of space within the material which is occupied by binding material only.

From the foregoing it will also be apparent that it is not only desirable to produce Waterproof material which is uniform throughout its extent 35 both from the standpoint of character of aggregate employed, but also from the standpoint of aggregate distribution, since otherwise some portions of the material will be less resistant to moisture or the passage of water than other m portions, or will exhibit some physical charac teristics different from other portions.

In view of the foregoing we not only carefully select the material to be employed as aggregate, but we also carefully process this material so that w all material used will have uniform physical. characteristics. In addition, we carefully grade the material as to size and proportion the amount of material of different grades included in the waterproof material.

We have found that the ordinary silica boulder, as found in nature, is an excellent material from which to manufacture the aggregate, or as it is sometimes termed the grit, going into the make-up of waterproof material. These 55 boulders are found at various places throughout the country and are of different size, although they are usually round or more or less regular in shape, presenting a smooth outer surface. They are glass-like in structure-i. e.. they are vitreous and amorphous. They, however, are not transparent as clear glass, but are white or colorless. They exhibit the physcal characteristics of glass or quartz, but are usually streaked or contaminated with a clay or silt-like substance, which may extend through the boulder in a stratified formation.

By the expression "silica boulder we mean naturally occurring silica or silicious material in the form of boulders. In other words, the word silica" indicates the material-which is widely distributed and of well-known chemical and physical compositionand the word boulder" indicates the size and shape thereof. See, for example, Webster's New International Dictionary, published in 1932 by G. 8; C. Merriam Co., of Springfield, Mass, pages 262-3; Boulder: Any detached and rounded or much worn mass of rock, distinctly larger than a cobblestone.

The process of forming aggregate or grit from these silica boulders is as follows: The silica boulders are first washed to remove such foreign material as can be removed in this way. They are then crushed and passed through a screen, preferably of about mesh. All material passing through the 20 mesh screen and retained on 150 mesh screen is used in the further carrying forward of the process. This mass of material is now sized and divided into four grades, by a screening operation. For convenience the grades may be referred to as A, B, C and D and we have found that satisfactory waterproof material may be made where the grading is carried through as follows:

Grade A, such material as passes through a 20 mesh screen and is retained on a 40 mesh screen.

Grade B, such material as passes through a 40 mesh screen and is retained on a 60 mesh screen.

Grade C, such material as passes through a 60 mesh screen and is retained on a 100 mesh screen.

Grade D, such material as passes through a 100 mesh screen and is retained on a 150 mesh screen.

The different grades of material are now separated one fromthe other and the separating operation may be, and preferably is done simultaneously with the grading operation and by any suitable means, such as are usually employed in grading and separating a mass of this character. The next step in the process is what may be termed a refining operation, in which the crushed material is subjected to sufficient heat to consume all combustible material contained within the mass and to disintegrate or break down other foreign matter into a dust or powder. We have found that in order to obtain the best results in the baking or refining operation, it is desirable, if not absolutely necessary, to grade the material prior to the baking operation, since in this way, particles of substantially the same size are subjected to the heating operation and there is little or no tendency for some of the particles to more effectively absorb and retain heat than other particles, consequently the heat can be more effectively applied.

In heating the coarser aggregate or grit it is desirable to apply as much heat as possible without causing the various particles of the mass to soften and frit together. We have found that this can be most effectively done where the grading of the grit is completed before the heating operation. The graded particles all being of about the same size, absorb approximately the same amount of heat and are heated to approximately the same temperature,.whereas if an ungraded mass of crushed material is heated some of the particles tend to soften and stick to other particles before the entire mass has reached the desired temperature. That is to say, by grading the particles before baking, an effective refining temperature may be employed for each grade which will insure the removal or subsequent removal of all deleterious material, such as vegetable matter, shale or clay, and which at the same time will not be sumciently high to occasion any fritting or any other deterioration in the crushed mass of silica material being treated.

The temperatures employed in the refining operation ranges from 1000 to 2000 F. with an average temperature of about 1750 F., although it has been found that grade A may, under certain conditions, be heated to about 3000 without causing the particles to frit together. It should also be said that under some conditions fairly satisfactory results can be ob-.

tained by employing considerably lower temperatures than those here designated, but in such cases a reagent such as stearic acid should be used in connection with the heating operation. We, however, have found that even where the reagent is employed temperatures about as herein designated should be employed to insure complete refining of the coarser aggregate or grit.

During the heating operation we prefer to subject the mass being heated to a tumbling operation, not only to keep the mass broken up but also to insure a uniform heating of all the particles of the mass. As will be more fully described in connection with the description of the apparatus employed in accomplishing the heating or baking, the mass while being baked is continuously agitated and is alternately assembled into a mass and spread by means of moving baffles, and is periodically caused to move or fall through the baking chamber in the form of rain so that each particle is not only subjected to the direct heat of the heating element, but is also moved into close proximity with the heating element.

After the heating operation the material is discharged from the oven and is again subjected to a screening operation. This is preferably accomplished in a rotary screen, and during this screening operation, the mass is subjected to a current of air of sufllcient intensity to blow away the dust and finer particles resulting from the refining and tumbling operation. The mesh of the screen employed and the pressure of the air is, of course, varied, depending upon the size of the particles, or the grade of the material. For example, grade A is passed over a 50 mesh rotating screen on being discharged from the oven; grade B over a 70 mesh screen; grade C over a 120 mesh screen; and grade D over a. 200 mesh screen; thus assuring that none of the crushed silica. material is lost, but also assuring that finer particles released or formed during the refining operation are separated out and removed.

The mass so graded and purified is now ready to be mixed with other grades of coarser aggregate or grit which have also been purified. In

accomplishing this mixing, we find that it is desirable not only to mix the various grades of coarser aggregate, but to also include the binding agent in the mixture. Wealso find that it is desirable to employ an air-tight rotary mixer in accomplishing this mixing, and that it is advantageous to mechanically deliver the coarser aggregate and the binding agent from storage bins to the mixer. The material going into the makeup of the aggregate is thus thoroughly mixed while dry. The mixing operation, with in the rotary mixer, is preferably continued for at least three minutes, and the dry mixture is then allowed to settle for at least about one minute before being removed from the mixer. The mixture may then be packed in sealed waterproof containers and the material so packed may be stored indefinitely before being used, or before being mixed with a liquid, such as water, in the final step of forming a waterproof material, such as plaster or paint.

The various grades of coarser aggregate going into the make-up of the aggregate for the waterproof material, are proportioned by weight so as to obtain maximum strength and maximum density of waterproof material. For example,

the mixture of the coarser aggregate preferably contains not less than 20% and not more than 30% of grade A, not less than 20% and not more than 40% of grade B, not less than 10% and not more than 20% of grade C, and not less than 5% and not more than 10% of grade D. As above stated, the binding agent is introduced into the mixture of aggregate in its dry form and we determine the voids in the final mass of coarser aggregate and then include a sumcient weight of a binding agent such as cement or waterproof cement, in such amounts as to overfill the voids by 5% to 10%.

From the foregoing it is apparent that the aggregate for the waterproof material is not only mixed so as to include the proper proportions of the various grades of grit and binding agent but that it is packed ready for shipment so that all the user has to do is to add sumcient liquid such as water, in amounts depending upon the desired consistency of the final mixture of waterproof material. This final mixing is done immediately prior to using the waterproof material and in much the same manner as mortar is mixed.

It is usually desirable to treat the crushed grit or coarser aggregate with a waterproofing material of such character as will permeate the pores of the different particles of the mass. This may be done at any time preferably after the initial grading and always before the final mixing of the crushed material. We have, however, found that the waterproofing of the separate grains or particles of the mass can be most satisfactorily accomplished during the refining operation and is best accomplished by employing a waterproofing material such as stearate of lead, which is not only capable of spreading over a large amount of surface,but is at least to some extent capable of permeating the particles of crushed silica boulder. During the refining operation and after the mass being refined is more or less uniformly heated, a waterproofing material, such as stearate of lead is introduced into the mass being treated and we have found that an amount of stearate of lead sufficient to make up about 1% to 2% of the mass being treated gives very satisfactory results. The tumbling and heating operation is during the process but continued after the waterproofing material has been added to the-mass.

. When this-procedure is followed it will be apparent that each particle of grit or coarser aggregate has been waterproofed before being included in the dry mix. p

'In the drawing accompanying and forming a part hereof Figure 1 is a longitudinal sectional view of a rotary oven, such as may be employed in carrying out the refining process heretofore described; and Fig. 2 is a transverse sectional view of the oven proper, the section being taken along the line II-II of Fig. l.

The rotary oven consists of a cylindrical shell 3 which is preferably lined with firebrick l or other suitable refractory material. The shell is mounted on suitably arranged rollers 5 and is guided in its rotation by annular bands 6, the rollers being flanged as shown. The shell is also provided with trunnions I suitably mounted in standards 8. A stove or heating element 9 extends centrally throughout the entire length of the shell. This heating element is preferably a resistance element suitably carried by refractory material which is shown in the form of a drum 10. Electric current is delivered to the heating element through a commutator or contact rings ll mounted on one of the trunnions l, in a manner well understood. Some means, not

shown, such as a thermostat-controlled cut-out or rheostat may be employed for controlling the flow of current and for adjusting and maintaining the desired temperature within the oven.

As shown, each trunnion i is mounted as an integral part of an end plate l4 which is suitably secured to one end of the cylindrical shell. Any suitable means, such as a motor or a belt drive may be employed for rotating the shell 3 and the driving means will preferably be operatively connected to one of the trunnions I.

As shown in the drawing, the interior of the shell is provided with a series of scoops it which extend throughout the length of the shell and project more or less radially from the refractory lining toward the drum l0. These scoops l5 do not extend along radial lines, but rather along lines approximately tangent to the drum, although the scoops are of such length that they extend only about half way across the intervening space between the refractory lining and the drum ill. The interior of the shell is also provided with a bailie l6, which may be termed a spreader. A screen I! extends across the interior of the shell and throughout its entire length. This screen is a wide mesh screen and it, together with the baille l6 and scoops ii are preferably formed of heat resisting metal. The screen is located on one side of the stove and in effect separates the interior of the oven into .two

parts, one of which includes the scoops, baffle and stove and the other of .which includes at least two spiral bafiies l8, which are so arranged that they collect the material and guide it to a central point between the ends of the shell.

'In operation, the shell rotates in the direction of the arrow associated with Fig. 2. The shell is first turned to a position such that a port l9, formed therein and extending through the refractory lining, is located on the upper side of the shell. The closure 20 for this port is then removed and a mass of graded material to be refined is delivered to the interior of the shell which has been preliminarily heated through the agency of the heating element 9. The port is then closed and the rotation of the shell is started. During central pile midway between the ends of the shell, I

and then distribute it lengthwise of the shell.

It is apparent that during the rotation the mass of material within the shell, in falling on the spreader I6, is spread longitudinally of the shell and is directed by the spreader onto one or more of the scoops ll. During the rotation these scoops retain the mass throughout a short are of movement and then, in effect, pour it onto the stove or at least cause it to fallthrough the central portion of the shell and close to the stove. The mass so discharged from each scoop is either caught by the screen or one of the other scoops, but eventually passes through the screen and is collected by the spiral bailles II, which guide the tumbling material toward the dischargeport. L1. As the drum continues to rotate the centralized mass is again spread by the spreader II and the cycle above described is repeated. It will be apparent that the spreader It, the scoops I l and the screen" act somewhat as paddles except-that the separate particles pass back and forth through the screen during the rotation of the shell.

I have shown a test port II, which opens into the interior of the shell and, as illustrated, is located opposite to the port It. This port consists'essentially of a pipe or passage, which extends through the shell and the refractory lining and is provided with a valve 22 for the purpose of. closing it. When it is desired to take a sample of the material being subjected to the refining operation, a receptacle, such as 23, is placed over the end of the passage and the valve 22 is opened as the port 2i moves to its lowermost position. In this way a sample of material being treated may be delivered to the receptacle 23 and the port 2i may then be immediately closed.

The treated mass is discharged from the shell by turning the shell to the'position shown in the drawing at which the port I! occupies its lowermost position. The closure 20 is then removed and the spiral baiiles act to guide the material through the port. It may be that the shell will have to be given one or two turns in order to discharge all of the material.

The port I9 may discharge into a chute for conveying the material direct to the rotary screen and as a matter of convenience wehave employed chutes and bins for conveying the material so that it does not have to be handled even during the first grading operation. V

Waterproof plaster or paint, having a coarser aggregate such as herein set forth, has, among others, the following characteristics and advantages: It is workable even in extremely cold and extremely warm weather, and the extreme changes in weather conditions will not crack the material nor cause hair-check while the material is being applied. The material is easily applied either by brush, spray or trowel. In addition, the material has a fine texture, and retains its texture and consistency while being applied to masonry of any kind; consequently the operator or sculptor may bring forth the finest designs his art or skill permit him to develop. The material may also be applied in thinner coats than other similar materials and still retain its effectiveness as a waterproofing material.

It will be apparent that the separate operations which go to make up the method here described may be changed or modified or some may even be aosassr omitted, that additional operations may be included in the treatment of the grit or coarser a regate, that the percentages 'of the various grades going into the make-up of the coarser aggregate may be varied and that the apparatus for accomplishing the refining may be materially modified and all without departing from the spirit and scope of the invention as set forth by the appended claims.

What we claim is:

1. A method of preparing aggregate which comprises subjecting a mass of crushed silica boulder to a temperature somewhat below that at which the same becomes plastic, agitating the mass to pulverize organic matter, shale and clay contained therein, and then removing the latter. 2. A method of preparing aggregate for waterproof material which comprises grading crushed silica boulder, heating a graded mass of such to a temperature below that at which particles of said mass become plastic, tumbling the mass during the heating operation, and then screening and blowing the mass to remove organic matter, shale and clay contained therein.

. v3. A method of preparing aggregate for waterproof material which comprises grading crushed silica boulder, separately heating masses of such of difierent grades, removing organic matter, shale and clay from each mass after such heating, and then mixing different grades of the silica boulder so treated in predetermined portions.

' 4. A method of preparing aggregate for waterproof material which comprises grading crushed silica boulder, separately heating masses thereof of different grades to a temperature somewhat below that at which the particles of the mass become plastic, tumbling the mass during the heating thereof and removing organic matter, shale and clay therefrom, and then mixing difi'erent grades of the silica boulder so treated in predetermined proportions.

5. A method of preparing crushed silica boulder as a component of the aggregate of waterproofing material, which consists in subjecting a crushed mass of the silica boulder to a baking temperature while tumbling it and causing it to fall in the form of separate particles pasta heating element, and then screening the material so treated to remove organic matter, shale, clay and silt therefrom.

6. A method ofpreparing waterproof material comprising washing silica boulder, crushing and screening the same to eliminate material coarser than 20 mesh and finer than mesh, grading the balance into a plurality of sizes, isolating each such size from the other sizes, refining each size separately by subjecting it to sufiicient heat to consume combustible matter and reduce foreign inorganic matter to powder form but short of a sintering heat, subjecting the material to agitation during the refining heat treatment, re screening each so treated size while subjecting it to a current of air sufiicient to remove pneumatically the dust and finer particles produced by the heat and agitation, mixingv the various sizes in definite proportions and adding a binding agent.

7. A method of preparing waterproof material comprising washing silica boulder, crushing and screening the same to eliminate material coarser than 20 mesh and finer than 150 mesh, grading the balance into a plurality of sizes, isolating each such size from the other sizes, refining each size separately by subjecting it to a heat of about 1000-3000 F. to consume combustible matter of boulders, washing the and reduce foreign inorganic matter to powder form but short of a sintering heat, subjecting the material to agitation during the refining heat treatment, re-screening each so treated size while subjecting it to a current of air suiiicient to remove pneumatically the dust and finer particles produced by the heat and agitation, mixing the various sizes in definite proportions and adding a cement binder in an amount to overflll the voids between the particles by 5-10%. V

8. A method of preparing waterproof material which comprises starting with silica in the form boulders to remove impurities which are susceptible to such treatment, crushing said boulders, screening the crushed boulders to eliminate portions which are coarser than 20 mesh and finer than mesh, grading the 20-150 mesh material into a plurality of related sizes and simultaneously separating the sizes, refining each such size individually by heating the same to a temperature short of causing fusion while agitating it, screening each so-treated size and simultaneously pneumatically removing portions susceptible to such treatment, combining the sizes in predetermined proportions to produce an aggregate having minimum void spaces, and mixing in a cementitious binding agent in an amount to at least fill said void spaces.

9. A method of converting into a waterproof material for plaster-or paint a silicious material which occurs naturally as boulders and which is composed of more or less regular particles of silica contaminated with organic matter and clayey or silt-like impurities, which method comprises the steps of washing the material, crushing it, screening the same to eliminate portions coarser than 20 mesh and finer than 150 mesh, dividing the portion between 20 and 150 mesh, inclusive, into a plurality of related sized grades, subjecting each such grade individuallyto a heat-- refining which is short of sintering or fusing while under agitation, re-s'creening each such heat-refined grade on a screen finer than the smallest intentional size therein while pneumatically removing. portions susceptible to such a removal, and combining .these purified grades in definite proportions with each other and with a binding agent while all are in a dry state.

10. A method of preparing aggregate for waterproof material which comprises heating crushed silica boulder to a refining temperature which is, however, insufiiciently high to cause softening, treating the so heated silica boulder with a water-. proofing material and agitating the mass while still heating the same.

11. A method of preparing aggregate for waterproof material comprising heating crushed graded matically removing silica boulder to a refining temperature without softening it, adding sufficient stearate of lead during the heating to coat and permeate the particles of material and continuing the heating, while simultaneously tumbling the material, untfl it is thoroughly waterproofed.

12. A method of preparing aggregate for waterproof material comprising heating crushed graded silica boulder to a refining temperature without softening it, coating and permeating the particles during the heating with a waterproofing agent, and continuing the heating, with simultaneous agitation, until the material is waterproofed.

13; A method of making a dry waterproof mix for plaster-and paint which comprises washing and crushing silica boulder, eliminating as by screening those particles of material which fall outside the range of 20-150 mesh, dividing the 20-150 mesh material into a number of related grades in each grade of which the size of the particles falls within a relatively narrow range, heating each grade of material to a temperature within the range of 1000-3000 F. to refine the same without softening it, adding a waterproofing agent during the heating, agitating each such grade while continuing the heating until the waterproofing agent coats and permeates the refined material, regrading as by screening each grade while pneumatically removing portions susceptible to such a removal, recombining the refined, waterproofed grades in predetermined propations and mixing in a binding agent in a dry 5 e. 2

14. A method of making a dry waterproof mix for plaster and paint which comprises washing and crushing silica boulder, eliminating as by screening those particles of material which fall outside the range of 20-150 mesh, dividing the 20-150 mesh material into a number of related grades in each grade of which the size of the particles falls within a relatively narrow range, heating each grade of material to a temperature with-' in the range of 1000-3000 F, to refine the same without softening it, adding stearate of lead during the heating, agitating each such grade while continuing the heating until, the waterproofing agent coats and permeates the refined material, regrading as by screening each grade while pneu portions susceptible to such a removal, recombining the refined, waterproofed grades in predetermined proportions so as to produce an aggregate having minimum void spaces and mixing in a binding agent in a dry state in such amount as will somewhat overflll such void spaces.

' EDWARD H. CANON.

BENJAMIN C. CANON. 

